Ms. Smith is a 52-year-old female who presents to your office for a possible laparoscopic sigmoid colectomy. She states that she has no significant medical history other than diverticulitis. Her only previous surgery was a wisdom tooth extraction at the age of 21. She notes that the procedure was uneventful; however, she continued to have significant oozing from her gums for approximately 24 hours. On review of systems, she notes that she has always bruised quite easily as long as she can remember. Further questioning reveals that she may have also had menorrhagia, although this was never formally diagnosed. Her laboratory data reveal a normal complete blood count. Her coagulation panel is notable for a mildly elevated partial thromboplastin time (PTT) and a prolonged bleeding time.
1. What is the single best predictor of an inherited disorder of coagulation?
2. What are the two major categories of coagulation abnormalities and what symptoms are associated with each?
In order to understand congenital coagulation disorders, one must begin by briefly reviewing the steps of normal hemostasis (see Figure 53-1). Although it is not essential to memorize every step of the cascade, one must understand that there is an intrinsic pathway that is initiated by exposure of blood to collagen as may happen with endothelial damage and an extrinsic pathway that is initiated with exposure to tissue factor. These pathways converge with the activation of factor X and formation of the tenase complex, which initiates the final common pathway by converting prothrombin to thrombin, and finally fibrinogen to fibrin. It is also important to note that platelets not only are involved in forming the initial hemostatic plug but also serve as the surface on which the tenase complex assembles.
Coagulation cascade and laboratory assessment of clotting factor deficiency. (Reproduced, with permission, from Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. 18th ed. New York: McGraw-Hill Education; 2012. Figure 116.1. www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)
The single best predictor is the preoperative history and physical exam. Careful history taking is usually more revealing than preoperative coagulation studies.
The preoperative hematologic history should focus on whether or not the patient has ever experienced a previous episode of abnormal bleeding. If the patient has had a previous operation, he or she should be questioned regarding any complications related to bleeding or poor hemostasis intraoperatively or in the postoperative period. If the patient has not undergone a previous surgical procedure, the history should focus on prolonged or abnormal bleeding related to trauma, previous episodes of mucosal bleeding or epistaxis, a history of menorrhagia in women, extensive bleeding after ...